A disk drive, such as a magnetic disk drive, comprises a magnetic disk for use as a recording medium, spindle motor, magnetic head, and carriage assembly. The magnetic disk is disposed in a case. The spindle motor supports and rotates the disk. The magnetic head reads data from and writes data to the disk. The carriage assembly supports the head for movement relative to the disk. The magnetic head comprises a slider mounted on a suspension of the carriage assembly and a head section on the slider. The head section comprises a recording element for writing and a reproduction element for reading.
The slider comprises a bearing surface (air-bearing surface or ABS) opposed to a recording surface of the magnetic disk. The head slider is subjected to a predetermined head load produced by the suspension and directed to a magnetic recording layer of the disk. When the magnetic disk drive is operating, an airflow is produced between the rotating disk and head slider, and the ABS of the slider is subjected to a force (positive pressure) that causes the slider to fly from the recording surface of the disk, based on the principle of air lubrication. The head slider can be caused to fly with a gap from the recording surface of the disk by balancing this flying force with the head load.
In recent years, to meet the demand for increased recording density, increasing importance has been attached to reduction in head flying height and flying-height control in a low-height area, and development of technologies for dynamically controlling the head flying height has been rapidly advanced. Under the present circumstances, a flying gap between a magnetic disk and a slider of a magnetic head in the vicinity of a read/write element is 10 nm or less. Further, the gap between the read/write element and disk for read/write operation is reduced to approximately several nanometers by additionally using a technology (DFH) such that the magnetic spacing is controlled by making the read/write element project dynamically.
As a result, some problems have become apparent. For example, a lubricant applied to the disk surface is transferred to the ABS of the head slider flying above the magnetic disk, the magnetic spacing is enlarged, and the flying performance of the slider is rendered unstable.
The lubricant transferred to the ABS of the slider of the magnetic head is moved onto the air-outflow end face of the head slider by the airflow and accumulates there. If the transferred lubricant accumulates in excess, the flying height of the slider becomes unstable. Thereupon, a problem of high-fly write (HFW) occurs such that recording and reproduction signals are unstable. Further, there is such a problem that the reproduction signals vary when the magnetic disk drive is started up, since the lubricant diffuses and returns to the read/write element portion on the ABS side while the magnetic head is being unloaded with the disk drive off.